Analysis of the Periodic Motion in a Powder Rheometer and Development of a New Flowability Testing Method

Abstract

This study focuses on the periodic motion observed in the FT4 Powder Rheometer and aims to develop a new testing method to evaluate powder flowability. This new method is based on the autocorrelation analysis of the torque measurements. The test results of powders belonging to different Geldart’s groups show that the torque measurements are periodic and that the cycle time (period) depends on the flowability. When the powder cohesiveness increases, the oscillations’ amplitude and the cycle time increase. Conversely, a free-flowing powder exhibits a liquid-like behavior and shows almost no periodic motion.